-LRB- CNN -RRB- -- Melissa Huckaby , the former Sunday school teacher accused of kidnapping , raping and killing 8-year-old Sandra Cantu , will face additional charges that she tried to poison two people , including another 7-year-old girl .

Melissa Huckaby is charged with killing Sandra Cantu and attempted poisoning of second child .

A revised complaint against Huckaby , 28 , of Tracy , California , was made public just hours before she was due back in court on Friday .

The new charges caused another delay in the murder case , CNN afiliate KRON reported .

The complaint charged that Huckaby `` did willfully and unlawfully mingle a harmful substance with food or drink '' with the intent to harm the child , identified only as `` Jane M. Doe . ''

Another alleged poisoning victim was identified as Daniel Plowman , but no age or other information was immediately provided .

The latest charges also include one count of child abuse endangerment relating to the unidentified child , who was allegedly in Huckaby 's `` care and custody . '' Read the complaint -LRB- PDF -RRB-

Huckaby did not enter a plea in the Cantu slaying in her first two court appearances last month .

At an earlier hearing , Judge Linda L. Loftis agreed to keep the autopsy and toxicology reports under seal , citing a `` great danger of public outrage . ''

If convicted on the murder , rape and kidnapping charges , Huckaby , could face the death penalty or life in prison without parole , authorities said .

CNN 's Alan Duke and Jim Roope contributed to this report

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NEW : Melissa Huckaby charged with attempting to poison `` Jane Doe , '' 7

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Huckaby due in court to face charges in slaying of another 8-year-old

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She faces special circumstances including kidnap , rape by instrument

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Decision on whether to seek the death penalty will come later